Survey of Durum Production Practices, 2004
M. J. Ottman
Summary
Durum growers were surveyed in cooperation with the USDA’s National
Agricultural Statistics Service to determine production practices and their
effects on yield and protein in the 2004 growing season. The survey was
conducted in two regions: West (Yuma and La Paz counties) and Central
(Maricopa, Pinal, and Pima counties). These two regions represent about 96%
of the durum acreage. We obtained responses from 91 out of an estimated 195
durum growers (47%) representing about 38,000 out of 95,500 acres (40%).
Durum was grown following cotton (48%), vegetables (43%), or other crops.
The predominant soil texture was a sandy loam (36%), followed by clay loam
(26%) and sandy clay loam (26%). Herbicide was applied on 67% of the
acreage. The major varieties were Kronos (20%), WestBred 881 (18%), Kofa
(14%), and Duraking (11%). Border flood irrigation accounted for 77% of the
acreage, followed by furrow (11%), and level basin (10%). The crop was
typically irrigated 6 to 7 times. The average planting date (irrigation applied)
was December 19 in the Central region and January 7 in the West region. The
seed was planted at an average rate of 163 lbs/acre. Phosphorus was applied to
only a third of the acreage, but when it was applied, the rate averaged 67 lbs
P2O5/acre. Nitrogen rate averaged 210 lbs N/acre. Grain yield tended to be
higher following crops other than cotton grown on clay loam to sandy clay loam
soils. Increased yield was associated with early planting, certain varieties, high
N rate, and irrigation frequency. Higher protein content was associated with
previous crops other than cotton, border irrigation, early planting, and N rate.
This survey documents associations, not cause-and-effect relationships, among
durum production practices, yield, and protein.
Introduction
Research on agricultural practices has traditionally been done in small plots by varying one aspect of management,
called the treatment, and keeping all else constant. Clear conclusions can be drawn using this approach, but the
applicability of the results is limited to the specific location and set of growing conditions. A method of conducting
research that allows wider applicability of results is to correlate agricultural practices and yield from a large number
of fields. The question is often asked how the top producers obtain high grain yield and protein. The problem with
this approach is the accuracy of the information provided and the fact that correlation does not establish a cause-andeffect relationship. Nevertheless, some useful knowledge may be gained using survey methodology.
Procedures
A survey of durum production practices in 2004 was developed and sent to growers in two regions of Arizona:
West (Yuma and La Paz counties) and Central (Maricopa, Pinal, and Pima counties). These two regions contained
about 95,500 of the 99,000 acres of durum in the state in 2004, or about 96% of the durum acreage. We obtained
responses from 91 out of an estimated 195 durum growers (47%) representing about 38,000 out of 95,500 acres
(40%). Depending on the variable, 75 to 84 of the responses were useable since some values were either missing or
out of range. The information requested on the survey included town, previous crop, variety, herbicide applied,
irrigation system, soil texture, planting date, seeding rate, fertilizer application, and number of irrigations applied.
The survey responses were statistically analyzed using analysis of variance.
Forage and Grain Report (P-154) October 2007
11
Results and Discussion
Durum acreage in 2004 was roughly split between the West (56%) and Central (44%) regions, and grain yield and
protein in these regions was not significantly different (Table 1). The county with the greatest percentage of the
acreage was Yuma (36%) followed by Pinal (22%) and Maricopa (18%). Grain yield was highest in Yuma and
Pinal Counties, and grain protein was lowest in Maricopa County.
About half (48%) of the durum was planted after cotton and the other half after vegetables and other crops. When
the previous crop was cotton, durum yield and protein were lower compared to other previous crops.
The predominant varieties in terms of percentage of acreage were Kronos (20%), WestBred 881 (18%), Kofa (14%),
and Duraking (11%). Many varieties were grown in both regions, but some such as Kofa and Alamo were only
grown in the West region and others such as Ocotillo and Crown were only grown in the Central region. The
highest yielding varieties were Duraking in the West region and Mohawk in the Central region. We were not able to
detect differences in grain protein concentration among varieties.
Herbicide was usually applied to most of the acreage in the West region, whereas only about half of the acreage in
the Central region received a herbicide application. Herbicide application did not affect yield or protein.
The predominant irrigation system is border flood (77%) followed by furrow mainly in the Central region (11%) and
level basin mainly in the West region (10%). Some of the respondents with level basin irrigation systems may have
listed their irrigation system as border flood. We found no relationship between irrigation system and grain yield,
but higher grain protein was associated with border flood than furrow or level basin irrigation.
Durum was grown predominantly on sandy loam soil (36%) followed by clay loam (26%) and sandy clay loam
(26%) soil. Most of the clay loam soil was in the West region. Grain yield was lower on sandy loam soil compared
with the heavier soil textures, clay loam and sandy clay loam.
The average planting date was January 7 in the West region and December 19 in the Central region. February
plantings were associated with lower grain yield in the West region. In the Central region, higher protein was
observed in the December than January plantings.
The average seeding rate was 163 lbs seed/acre. No differences in yield or protein could be attributed to seeding
rate.
The average nitrogen rate was 210 lbs N/acre. In the West region, the highest protein content was associated with
nitrogen rates between 100 – 199 lbs N/acre. In the Central region, the highest yields were associated with nitrogen
rates between 300 – 499 lbs N/acre. The response of the durum crop to nitrogen fertilizer depends on several factors
that were not included in this survey such as manure application and soil nitrogen content.
Only about a third of the durum acreage received P fertilizer, but a higher percentage of the acreage in the Central
region received P fertilizer than in the West region presumably due to adequate soil P in the West from vegetable
production. When P fertilizer was applied, the average phosphorus rate was 67 lbs P2O5/acre. Application of P
fertilizer in the Central region was associated with slightly higher grain yield, but again, response to P fertilizer is
also influenced by other factors such as manure and soil P.
The average number of irrigations applied was 6.5. The number of irrigations applied was associated with yield in
both regions. In the West, grain yield increased as number of irrigations increased to seven, but decreased if more
than seven irrigations were applied. This trend may not be directly affected by irrigation number, but by the fact
that fewer irrigations are applied to later plantings and more irrigations are applied to lighter soils, both of which are
associated with lower yields. In the Central region, increased irrigation frequency is associated with higher yields.
This survey has shown that there are some associations between the various durum production practices and grain
yield and protein, but these associations do not imply a cause-and-effect relationship. Side by side comparisons are
the best way to evaluate the direct effect of varieties, fertilizer rates, or irrigation practices. Nevertheless, there
Forage and Grain Report (P-154) October 2007
12
appears to be an association between higher yields and previous crops other than cotton, certain varieties, clay loam
or sandy clay loam soil texture, early planting, high N rate, and irrigation number. Grain protein was associated
with previous crops other than cotton, border flood irrigation, early planting, and N rate.
Acknowledgements
I wish to thank the staff at the National Agricultural Statistics Service for designing and conducting the survey and
collating the results. I also wish to thank Larry Aleamoni, Head of the Special Education Department at the
University of Arizona, for his helpful suggestions on how to analyze the data. This project was funded by the
Arizona Grain Research and Promotion Council.
Forage and Grain Report (P-154) October 2007
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Table 1. Number of survey respondents (N), grain yield, grain protein, and percentage of acres represented by
various durum production practices in Arizona.
West
(Yuma and La Paz Co.)
N
Yield Protein Acres
lbs/a
%
%
Region
West
Central
Significance
County
Yuma
Pinal
Maricopa
LaPaz
Pima
Significance
Previous
crop
Cotton
Vegetables
Leaf lettuce
Alfalfa
Fallow
Head lettuce
Corn
Durum
Significance
Variety
Kronos
WPB881
Kofa
Duraking
Alamo
Ocotillo
Crown
Mohawk
Orita
Tacna
Matt
Platinum
Experimental
Significance
Central
(Maricopa, Pinal, and Pima Co.)
N
Yield Protein Acres
lbs/a
%
%
N
All
(West and Central)
Yield Protein Acres
lbs/a
%
%
43
---
6022
-----
14.0
-----
56
---
--41
--5834
---
--13.6
---
--44
43
41
6022
5834
NS
14.0
13.6
NS
56
44
36
----7
---
6133
----5447
-----
14.0
----14.0
-----
43
----13
---
--22
18
--1
--6008
5645
--5400
---
--14.0
13.3
--12.5
---
--23
15
--6
36
22
18
7
1
6133
6008
5645
5447
5400
+
14.0
14.0
13.3
14.0
12.5
+
43
23
15
13
6
7
20
6
4
--4
-----
5955
6038
5886
6100
--6825
----NS
13.6
13.7
14.6
14.8
--14.4
----NS
9
31
9
3
--3
-----
36
----1
2
--1
1
5768
----7300
6000
--7400
4850
NS
13.6
----13.6
13.5
--16.0
14.0
NS
40
----0
3
--1
1
43
20
6
5
2
4
1
1
5798
6038
5886
6340
6000
6825
7400
4850
+
13.6
13.7
14.6
14.6
13.5
14.4
16.0
14.0
+
48
31
9
3
3
3
1
1
11
8
17
6
10
----3
1
1
--1
1
6225
5467
6550
7000
5762
----5600
----------*
13.7
14.3
14.0
15.5
14.1
----------------NS
12
10
14
6
9
----3
0.4
0.8
--0.3
0.2
12
3
--4
--11
10
6
7
--1
-----
5708
4450
--5867
--5443
5663
7023
6657
--------*
13.8
12.8
--13.0
--13.9
13.2
14.5
13.6
--------NS
8
8
--6
--7
7
4
4
--0.3
-----
23
11
17
10
10
11
10
9
8
1
1
1
1
5907
5060
6550
6320
5762
5443
5663
6548
6657
--------**
13.8
13.7
14.0
14.7
14.1
13.9
13.2
14.5
13.6
--------NS
20
18
14
11
9
7
7
7
5
0.8
0.3
0.3
0.2
Forage and Grain Report (P-154) October 2007
14
Table 1 (Con’d). Number of survey respondents, grain yield, grain protein, and percentage of acres represented by
various durum production practices in Arizona.
West
(Yuma and La Paz Co.)
N
Yield Protein Acres
lbs/a
%
%
Herbicide
applied
No
Yes
Significance
Irrigation
system
Border
Furrow
Level basin
Drip
Significance
Soil
texture
Sandy loam
Clay loam
Sandy clay
loam
Loam
Clay
Silt loam
Sand
Silty clay
Significance
Planting
date
December
January
February
Significance
Seeding rate
(lbs/a)
120-135
140-155
160-175
180-229
Significance
Nitrogen rate
(lbs N/a)
0-99
100-199
200-299
300-499
Significance
Central
(Maricopa, Pinal, and Pima Co.)
N
Yield Protein Acres
lbs/a
%
%
N
All
(West and Central)
Yield Protein Acres
lbs/a
%
%
7
36
5688
6086
NS
14.4
13.9
NS
9
47
22
19
5872
5789
NS
13.5
13.8
NS
24
19
29
55
5828
5984
NS
13.7
13.8
NS
33
67
35
--7
1
6034
--5982
5850
NS
14.1
--13.4
14.0
NS
46
--9
1
25
14
2
---
5879
5758
5795
--NS
13.9
13.3
12.9
--+
31
11
1
---
60
14
9
1
5970
5758
5940
5850
NS
14.0
13.3
13.3
14.0
*
77
11
10
1
12
16
5963
6123
13.9
14.0
18
21
20
7
5559
6156
13.5
14.0
18
5
32
23
5711
6133
13.7
14.0
36
26
9
3
1
1
--1
6196
5845
5000
5500
--5600
NS
13.9
13.9
14.5
14.0
--13.3
NS
10
5
0
2
--1
10
1
1
--1
---
6356
5500
5500
--4850
--NS
13.5
13.5
13.4
--14.0
--NS
15
1
2
--1
---
19
4
2
1
1
1
6280
5759
5250
5500
4850
5600
*
13.7
13.8
13.8
14.0
14.0
13.3
NS
26
6
2
2
1
1
18
17
7
6101
6148
5514
**
14.2
13.9
13.3
NS
20
28
11
29
9
---
5904
5678
--NS
13.8
13.0
--+
28
14
---
47
26
7
5980
5985
5514
*
13.9
13.6
13.3
NS
48
42
11
9
12
11
9
6102
6044
6138
5774
NS
14.3
13.6
13.7
14.3
NS
8
20
14
18
0
9
16
12
--6072
5912
5590
NS
14.0
13.6
13.6
13.6
NS
0
10
15
16
9
21
27
21
6102
6056
6004
5669
NS
14.3
13.6
13.7
13.9
NS
8
29
29
34
3
9
25
6
5671
5940
6098
6002
NS
13.5
14.7
13.7
14.2
+
3
6
36
11
7
11
15
8
5866
5582
5668
6463
*
13.8
13.5
13.8
13.4
NS
10
7
14
13
10
20
40
14
5807
5743
5937
6265
NS
13.7
14.0
13.8
13.7
NS
13
14
50
23
Forage and Grain Report (P-154) October 2007
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Table 1 (Con’d). Number of survey respondents, grain yield, grain protein, and percentage of acres represented by
various durum production practices in Arizona.
West
(Yuma and La Paz Co.)
N
Yield Protein Acres
lbs/a
%
%
Phosphorus
applied
No
Yes
Significance
Number of
irrigations
<6
6
7
>7
Significance
All
Central
(Maricopa, Pinal, and Pima Co.)
N
Yield Protein Acres
lbs/a
%
%
N
All
(West and Central)
Yield Protein Acres
lbs/a
%
%
33
10
6037
5972
NS
13.9
14.1
NS
44
12
19
22
5751
5906
*
13.7
13.6
NS
21
23
52
32
5932
5926
NS
13.8
13.8
NS
65
35
14
13
8
8
5912
6215
6441
5479
*
13.8
13.9
14.2
14.1
NS
17
18
11
14
6
14
8
10
5951
5343
5885
6400
*
13.4
13.6
13.7
13.8
NS
12
14
6
8
20
27
16
18
5924
5763
6163
5991
*
13.6
13.7
13.9
13.9
NS
28
32
17
22
43
6022
14.0
56
41
5834
13.6
44
84
5930
13.8
100
Significance: Statistical significance or probability that differences observed are due to chance. NS = not
significant at the 10% probability level, + = significant at the 10% probability level, * = significant at the 5%
probability level, and ** = significant at the 1% probability level.
Forage and Grain Report (P-154) October 2007
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